1. Field of the Invention
The invention relates to a simple low powered system for tracking the sun from east to west on a day by day basis with daily adjustment for time of sunrise and sunset as well as adjustment for the appropriate declination in accordance with the time of day and date to accurately face the sun during its traversal of the sky, even when the sun is hidden behind clouds.
2. Description of the Prior Art
Systems for tracking the sun are well known in the art. Such systems in the past have mainly encompassed the use of photo-responsive electrical devices and electrical circuitry connected thereto which determine the direction of sun movement relative to the photo-responsive devices and continually, via the electronic or electrical circuity, realigning the system so that the sun was always at the center of the photo-responsive device. Systems of this type are expensive to operate and difficult to service when knowledgeable personnel are not available. Furthermore, such devices can only track the sun when the sun is visible. Often, when the sun is blocked by clouds or other interfering elements for excessive periods of time, the optical tracks completely lose the sun and are unable to pick it up and track it when it again becomes visible.
In order to track the sun, it is necessary to calculate the location of the sun at any time of the day for the geographical located involved.
When dealing with the sun and its angular relationship with any geogrphical location, it is also neccessary to use "SOLAR TIME" and declination.
Declination is the angular difference of the sun's position with respect to the equator, being north of the equator in the summer and south of the equator in the winter, the variation being approximately sinusoidal and thus can be approximated by a crank. Solar time does not coincide with local clock time much of the time. It is necessary to convert standard time to solar time by applying two corrections. First, there is a constant correction for any difference in longitude between the location and the meridiam on which local standard time is based. (75, 90, 105 and 120 degrees west longitude in the continental United States). The second correction is the EQUATION OF TIME, which takes into account the various perturbations in the earth's orbit and rate of rotation which effect the time the sun appears to cross the observer's meridan. The correction is obtained from published charts and tables.